1. Field of the Invention
The invention concerns an insulation-piercing connector for coaxial cables adapted to be mounted on a support on equipment to be served by the cable or on a plug or socket connector, either before or after connection to the coaxial cable, and to provide a branch connection, possibly without any intermediary member, between the circuitry of the equipment and the coaxial cable.
2. Description of the Prior Art
The increase in use of coaxial cables for interconnecting transmitting and/or receiving equipment, in local area networks comprising multiple stations, for example, has led to the development of insulation-piercing connectors for connecting equipments in parallel along a common, shared cable.
In many cases, and especially in networks where the configuration is likely to change, there is a requirement to preserve the integrity of the cable to the greatest possible degree, which means avoiding the use of removable Tee branching connections, as these make it necessary to divide up the cable and to provide it with plug-in sockets for the connectors, or connectors which require notching the cable at the location of the insulation-piercing connectors to obtain access to the core.
In either case the operation on the cable is irreversible and therefore usually a problem in the event of reconfiguration.
To avoid this disadvantage insulation-piercing connectors have been proposed in which the branch connection is made by connecting spikes which penetrate the coaxial cable transversely, through the protective sheath covering it, to become embedded either in the tubular outer conductor or in the central core.
The core connecting spike, usually called the "probe", is generally covered by an insulator at least in the part that is designed to penetrate the cable and excluding its end at which it is embedded in the core of the cable. This insulator is designed to eliminate the risk of the probe short-circuiting the cable, especially where the outer conductor is formed by a tubular braid of conductive wires.
To minimize the damage to the coaxial cable by the connecting spikes the dimensions of the part of the spikes which penetrates the cable are minimized. A compromise has to be arrived at to enable the spikes to withstand the forces exerted on them when the connector is mounted on the cable and in particular when they penetrate the cable.
It is known to pre-pierce holes in the cable at the locations provided for the connectors in order to facilitate penetration of the probes to the cable core, which enables the diameter of the probes to be reduced commensurately.
The pre-pierced hole for a probe is preferably made after the cable has been finally positioned and immobilized in the connector, and the conduit through which the probe is inserted and in which it is immobilized is used to form the pre-pierced hole. This solution makes it possible to exploit the piercing guide that this conduit can form and to avoid trial and error placing of the probe which would result from piercing the cable before immobilizing it in the connector.
It is also known to associate with the probe a spring device which presses its end against the core that it penetrates, in order to ensure that the contact established between the probe and the core remains constant with time.
The solutions described hereinabove, used in the disclosure of European patent No. 0109229 in particular, are also used in the embodiment described in this application, one objective of which is to propose a secure and reliable insulation-piercing connector that is simple to manufacture and install and causes virtually no damage to the cable.
Another objective of the present invention is to propose an insulation-piercing connector adapted to be positioned on a support on equipment to be served by the cable or on a plug or socket attached to the cable either before or after the connection is made to the coaxial cable.
Positioning the probe after pre-piercing the cable implies mounting the connector onto the cable before the connector is fixed to its support and electrically connected to the equipment to be served or to the plug or socket, when the probe is housed in the base member by which the connector is fixed and is inserted through an opening under this base member, that is to say in the surface of the latter which normally bears against the support.
The need to mount and connect a connector to a cable before mounting it on and connecting it to the user equipment is a disadvantage in various cases, for example if the equipment is provided with a fixed insulation-piercing connector designed to be connected to a coaxial cable only at the point of installation, as is the case with numerous equipments sold in cases without their external connecting cables.
Consequently, the present invention proposes an insulation-piercing connector for coaxial cables adapted to be mounted on a support on equipment served by the cable or on a plug or socket, either before or after connection to the coaxial cable, and optionally to provide a branch connection without any intermediary member between the electrical circuitry of the equipment and the coaxial cable.